Thermal gradient fluid header for multiple heating and cooling systems

ABSTRACT

Apparatus and method for heating/cooling buildings and other facilities. An elongate pipe filled with water or other fluid medium forms a thermal gradient header having temperature zones that are progressively warmer towards one end and cooler towards the other. Multiple heating/cooling systems are connected to the header so as to draw fluid from zones that are closest in temperature to the optimal intake temperature of each system, and to discharge fluid back to the header at zones that are closest to the temperature to the optimal output temperature of each system, allowing each heating/cooling system to take advantage of the thermal output of other systems. The pipe forming the thermal gradient header may be routed back and forth in the facility to define a series of legs containing the different temperature zones. A boiler or other source may supply makeup heat to the thermal gradient header, and excess heat may be sent from the header to a ground field or other thermal reservoir for later use.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/459,724 which was filed Jul. 6, 2009 and claims the benefit of U.S.Provisional Patent Application Ser. No. 61/133,848 filed on Jul. 3,2008.

BACKGROUND

a. Field of the Invention

The present invention relates generally to heating and cooling systemsfor buildings and other facilities, and, more particularly, to anapparatus and method in which the efficiency of heating and coolingsystems for a building or other facility is maximized by drawing anddischarging water, or another fluid medium, from an elongate headerhaving a hot-to-cold thermal gradient existing along its length, withthe intake and discharge points being located along the gradient tooptimize the intake and discharge temperatures of each of theheating/cooling systems.

b. Related Art

Maximizing the efficiency of heating and cooling systems has been a goalsince time immemorial, but has recently been given greater impetus byrapidly escalating energy costs.

Most modern heating and cooling systems utilize some form of fluidmedium for thermal transfer, typically water. For example, a heat pump(water-to-water or water-to-air) or an air handling unit may take incool water and discharge it at a slightly higher temperature or viceversa, depending on whether it is in a cooling or heating mode. Variousother systems intake/discharge water at different temperatures tosupport their heating/cooling operations; the intake/output temperatureparameters and differentials vary widely depending on the nature of thesystem and the mode and condition in which it is operating at aparticular time, with some systems having either or both of the waterinput and output at relatively mild temperatures and others operatingmore towards the extremes of hot/cold.

Such systems are commonly optimized for efficiency on an individualizedbasis, for example, by heating/cooling the incoming water (or othermedium) to reduce thermal load of the operation, and/or similarly bycooling or heating the discharge flow to reduce thermal losses.Nevertheless, a degree of inefficiency is inevitable, in significantpart due to the differences between optimal intake temperatures for thesystems and the actual temperatures of the sources from which the wateris drawn. Ultimately, in most facilities some greater or lesser amountof excess thermal energy is created, which is then discharged to theoutside air (e.g., free cooling) or otherwise rejected into theenvironment and thereby lost/wasted. Given the large number and varietyof systems that are commonly found in modern buildings, especially inlarge facilities or complexes, the total loss due to the cumulativeinefficiency of the multiple systems can be very great, even though eachsystem is relatively efficient by itself.

Accordingly, there exists a need for an apparatus and method forincreasing efficiency and reducing thermal energy loss for multipleheating and cooling systems that operate on combination in buildings,complexes and other facilities. Furthermore, there exists a need forsuch an apparatus and method that can be utilized with the manydifferent types of heating and cooling systems that may exist throughouta building, complex or other facility. Still further, there exists aneed for such an apparatus and method that can be employed on aneconomical basis, both in terms of operation and initial capitalexpenditure, so as to achieve significant cost savings when taken as awhole.

SUMMARY OF THE INVENTION

The present invention addresses the problems cited above, and providesan apparatus and method for increasing efficiency of heating and coolingsystems for buildings and other facilities.

Broadly, the apparatus comprises (a) an elongate thermal gradient headerhaving at least one zone containing fluid at a relatively highertemperature and at least one zone containing fluid at a relatively lowertemperature; and (b) a plurality of heating/cooling systems that drawthe fluid from the thermal gradient header and discharge the fluid backthereto, each of the heating/cooling systems having an intake connectedto a first one of the zones of the header that contains the fluid at atemperature closer to an optimal intake temperature of theheating/cooling system, and a discharge connected to a second of thezones that contains the fluid at a temperature that is closer to anoptimal discharge temperature of the system. The plurality ofheating/cooling systems may comprise multiple heating/cooling systemsthat operate in combination in a building or other facility, that areconnected to the thermal gradient header so that some of the systems aredrawing from zones of the header fluid that has been discharged to thezones by other of the heating/cooling systems that are connected to theheader.

The thermal gradient header may comprise an elongate pipe containing thefluid. The fluid contained in the thermal gradient header may be water.The temperature zones of the header may be formed by legs of the pipethat are routed through the building or other facility. Theheating/cooling systems connected to the thermal gradient header maycomprise, for example, heat pumps, air handling units, air conditioningunits, refrigeration units, water heaters, ice plants, and so on.

The apparatus may further comprise means connected to the thermalgradient header for providing makeup heat if necessary, and theapparatus further comprise means connected to the thermal gradientheader for rejecting excess heat if necessary. The means for providingmakeup heat may be, for example, a boiler heat exchanger, and the meansfor rejecting excess heat may be a fluid cooler. The means for rejectingexcess heat may also comprise a thermal reservoir from which heat may berecovered during a subsequent period of operation. The thermal reservoirmay comprise a ground source thermal field.

The thermal gradient header may comprise multiple legs, each containingfluid at progressively cooler temperatures from hot to cold. Themultiple legs may comprise, progressively, a hot water leg, a warm waterleg, a cool water leg and a chilled water leg. The legs of the thermalgradient header may be defined by runs of the pipe between sections ofthe building or other facility. The runs may be routed back and forthbetween a mechanical room and distribution areas of the building orother facility.

The apparatus may further comprise a plurality of pumps associated withthe systems, that each circulate the fluid from a first leg of theheader, through the system, and back to a second leg of the header. Theheating/cooling systems may be connected to the header by intake anddischarge lines through which the fluid is circulated by the pumps. Theapparatus may further comprise one or more crossover lines thatinterconnect the intake and discharge lines, so that the fluid can beselectively circulated through the heating/cooling systems without beingdrawn from/discharged to the thermal gradient header.

The apparatus may further comprise one or more control valves that areselectively operable to allow the heating/cooling systems to drawfrom/discharge to the different legs of the thermal gradient header,depending on operating conditions of the individual heating/coolingsystems.

Broadly, the method comprises the steps of (a) providing an elongatethermal gradient header having at least one zone containing fluid at arelatively higher temperature and at least one zone containing fluid ata relatively lower temperature, and (b) supplying the fluid from thethermal gradient header to a plurality of heating/cooling systems, thestep of supplying the fluid from the thermal gradient header to theplurality of heating/cooling systems comprising drawing the fluid fromthe thermal gradient header for each heating/cooling system from a firstone of the zones that contains the fluid at a temperature closer to anoptimal intake temperature of that system, and then discharging thefluid from the system to a second of the zones of the header thatcontains the fluid at a temperature that is closer to an optimaldischarge temperature of that system. The step of discharging the fluidback to the second zone of the thermal gradient header may comprisedischarging the fluid back at a lower temperature or a highertemperature than that at which the fluid is drawn from the first zone ofthe header.

The step of supplying fluid from the thermal gradient header to aplurality of heating/cooling systems may comprise supplying the fluid tomultiple heating/cooling systems that operate in combination in abuilding or other facility, that are connected to the thermal gradientheader so that some of the systems draw from zones of the header fluidthat has been discharged to those zones at near optimal intaketemperatures by others of the heating/cooling systems.

The step of providing a thermal gradient header may comprise providingan elongate pipe that contains the fluid. The fluid may be water. Thestep of providing the thermal gradient header may comprise routing theelongate pipe so as to form multiple legs of the header that define thetemperature zones thereof, containing fluid at progressively coolertemperatures from hot to cold.

The step of supplying fluid from the thermal gradient header to theplurality of heating/cooling systems may comprise drawing the fluid fromthe header using pumps that are associated with the heating/coolingsystems and that circulate the fluid through the heating/cooling systemsand back to the receiving next legs of the header.

The step of supplying the fluid to a plurality of heating/coolingsystems may further comprising selectively operating one or more controlvalves to allow the heating/cooling systems to draw from/discharge tothe different legs of the thermal gradient header, depending onoperating conditions of the heating/cooling systems.

These and other features and advantages of the present invention will bemore fully understood from a reading of the following detaileddescription with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary building having multipleheating/cooling systems, showing the manner in which various loads areplaced on these systems;

FIG. 2 is a diagrammatic view of a thermal gradient header in accordancewith the present invention, with four principal zones of temperaturebeing identified along the length of the header, namely, hot water (HW),warm water (WW), cool water (CW) and chilled water (CHW);

FIG. 3 is a diagrammatic view of an elongate thermal header, similar tothat of FIG. 2, installed in an exemplary building, the header beingrouted circuitously between the mechanical room and buildingdistribution so that each of the four principal temperature zonesidentified in FIG. 2 is available to be accessed by system connectionsin both areas;

FIG. 4 is a diagrammatic view of exemplary connections of a water-to-airzone heat pump to the thermal gradient header of FIG. 3, the legs of theheader forming the four temperature zones being shown in cross-section,the zone heat pump being provided with connections to the hot, warm andcool water sections of the header, to draw from and discharge theretodepending on the mode of operation of the heat pump;

FIG. 5 is a diagrammatic view, similar to FIG. 4, showing theconnections of a dehumidification heating source to the hot and warmlegs of the header;

FIG. 6 is a diagrammatic view, similar to FIG. 4, showing theconnections of duct-mounted heat coils to the hot and warm legs of theheader;

FIG. 7 is a diagrammatic view, similar to FIG. 4, showing theconnections of a domestic hot water heating system into the warm andcool legs of the header;

FIG. 8 is a diagrammatic view, similar to FIG. 4, showing theconnections of an exhaust heat pump to the hot, warm, cold and chilledlegs of the header;

FIG. 9 is a diagrammatic view, similar to FIG. 4, showing theconnections of a water-cooled heat pump to the hot, warm, cool andchilled legs of the header;

FIG. 10 is a diagrammatic view, similar to FIG. 4, showing theconnections of a makeup air unit to the hot, cool and chilled legs ofthe header;

FIG. 11 is a diagrammatic view, similar to FIG. 4, showing theconnections of an ice plant heat exchanger to the hot, warm, cool andchilled legs of the header;

FIG. 12 is a diagrammatic view, similar to FIG. 4, showing theconnections of an ice rink air handling unit to the hot, warm, cool andchilled legs of the header;

FIG. 13 is a diagrammatic view, similar to FIG. 4, showing theconnections of a boiler heat exchanger to the hot and chilled legs ofthe header; and

FIG. 14 is a diagrammatic view, similar to FIG. 4, showing theconnections of a fluid cooler to the hot and warm legs of the header.

FIG. 15 is a block diagram illustrating a typical prior art approach toachieving thermal efficiency between heating/cooling systems in afacility, showing the discharge of heat through free cooling and heatrejection and the inherent inefficiency resulting therefrom;

FIG. 16 is a block diagram, similar to FIG. 15, illustrating sharing ofloads between heating/cooling systems in a facility utilizing a thermalgradient header in accordance with the present invention, showing thereduced thermal losses and increased efficiencies achieved thereby; and

FIG. 17 is a diagrammatic view of a thermal gradient header inaccordance with the present invention, installed in a facility such asthat in FIG. 1 and having a plurality of heating and cooling systemsconnected thereto so as to operate in combination to provide heating andcooling to the facility in an energy efficient manner.

DETAILED DESCRIPTION

FIG. 1 shows an exemplary building at 10 having multiple heating andcooling systems installed therein. In this example, the building 10 is acommunity sports center, a type of facility that typically includesheating/cooling systems that are especially energy intensive andchallenging to operate in an efficient manner, including, for example,various heating/cooling systems associated with swimming pools, icerinks, gym rooms, arenas, and so on. It will be understood, however,that the present invention may be implemented in connection with anyfacility having heating and cooling systems, whether involving single ormultiple buildings.

In accordance with the present invention, the various heating/coolingsystems in the building that rely on water (or other liquid median) totransfer energy are connected at various points along a header that isfilled with water (or other suitable liquid medium). The header issuitably an elongate pipe, with the temperature of the water in the pipebeing in a continuous thermal gradient from hot at one end to cold atthe other. Therefore, at one end of the header the water will behottest, then moving towards the other end it will progressively cooler,from warm to cool then coldest. The exemplary systems described hereinbelow utilize water as the fluid forming the thermal medium, but it willbe understood that other suitable fluids may be used in someembodiments. Furthermore, it will be understood that the term “water”,as used in this description and the appended claims, includes not justpure and substantially pure water, but also water including variousadditives, dissolved materials, impurities, and other substances.

Each system is connected to the header with an intake located on theheader at a point where, based on the gradient, the temperature will beclosest to the ideal for operation of that system, from an energyefficiency standpoint. The discharge, in turn, is connected to theheader at a point where, again based on the gradient, the temperature ofthe water therein will most closely match the optimal-temperaturedischarge from the system. For example, if one system optimally requireswarm water for intake and discharges it at a cool temperature, then itsintake will be positioned at a point along the header at which, due tothe gradient, the water contained therein is normally warm, and thedischarge will be connected at a different point where the water in theheader is normally cool. If another system, in turn, optimally requirescool water for intake and discharges it warm, its intake connection willbe located at a cool segment of the header and the discharge connectionwill be at a warm segment, which will be proximate the intake connectionof the first system. The first system which will therefore pick up thewater discharged from the second, which is now at near optimaltemperature for the first system, and then discharge it back into thecool zone of the header as described above.

Consequently, use of the thermal gradient header achieves verysignificant energy savings by matching the water output temperatures ofsome systems to the preferred intake temperatures of others. Forexample, a system that optimally operates with a warm intake flow anddischarges it hot need not expend energy first heating the water fromcold to warm, as is the case with some prior installations; furthermore,the hot water passing out of the system does not constitute “waste heat”(which some prior systems attempt to recover, albeit with losses), sinceit is simply discharged back into the header where it is already at atemperature and location optimal for use by some other system. The sameholds true for systems that draw water at a warmer temperature and thendischarge it at a cooler temperature. The various systems thus cooperatein meeting the heating and cooling requirements of the building or otherfacility, with (as will be described below) make up heat being added tothe header or excess heat rejected only at times of extremes cold orheat (e.g., winter or summer) when the building requirements cannot bemet by the operation of the systems themselves.

An example header 20 is shown diagrammatically at FIG. 2. In thisinstance, the header is shown as being divided into four zones, namely,hot water (HW) 22, warm water (WW) 24, cool water (CW) 26 and chilledwater (CHW) 28. As will be described in greater detail below, thesesegments correspond to each of four legs of the header that are routedthrough the interior of the building; depending on installation, theremay be fewer or more legs and corresponding zones in the header,depending on the manner and number of times the header is routed throughthe building or other facility. The foregoing designations (i.e., HW,WW, CW, CHW) express the relative temperatures of the water contained ineach of the legs, however, it will be understood that the temperaturewithin the header will generally follow something of a continuum fromhot to cold, rather than being divided into sharply defined zones. Itwill also be understood that the header, which is suitably an elongatepipe with associated connections and valves, in most embodiments doesnot itself include any pumps or means for forcing flow of water from oneend to the next, with such flow as exists therein generally beingcreated by the pumps of the various systems as they draw and dischargewater to and from the header.

As can be seen in FIG. 3, the header is suitably routed through theinterior of the building 10 in a circuitous manner, back and forthbetween the building distribution 30 and the mechanical room 32, so thateach of the four legs and associated temperature zones ((HW) 22, (WW)24, (CW) 26, (CHW) 28) is accessible in each area. This makes itpossible for each heating/cooling system, regardless of whether it islocated in the mechanical room or distribution area, to be connected topoints along the header at which the intake and discharge temperaturesare optimal, as described above.

For example, FIG. 4 shows the connections of a water-to-air heat pump34, which could be located in either the building distribution area orthe mechanical room. As is well known, a heat pump is normally able toperform both heating and cooling functions, typically operating in theformer mode during winter and the latter mode during summer. In bothmodes, the heat pump optimally intakes warm water, which when in theheating mode it discharges at a slightly lower temperature as coolwater, and when in the cooling mode it discharges at a slightly highertemperature as hot water, heat having been either extracted from oradded to the water as a part of the operating cycle of the heat pump.

Thus, in accordance with the present invention, the zone heat pump 34 isinstalled with an intake line 36 that is connected to the warm water leg24 of the elongate thermal gradient header in this case, within thebuilding distribution area 30 (see FIG. 3), by a connector line 38.Water is drawn from the warm water connection by a constant velocitypump 40, with intake being controlled by valve 42. The discharge line44, in turn, is connected to both the cool water and hot water legs 26,22 of the header, via connector lines 46, 48, with flow to each beingcontrolled by valves 50, 52. No connection is made to the chilled waterleg 28 in this case, since it is not needed to support either mode ofoperation (heating or cooling) of the zone heat pump.

Thus, when the zone heat pump 34 is in the heating mode, warm water isdrawn from header segment 24, via lines 38 and 36, and then dischargedback to the cool water leg 26 of the header via lines 44 and 46; whenthe heat pump is in the cooling mode, in turn, warm water is again drawnfrom segment 24, again via line 38 and 36, but the output is insteaddischarged to the hot water leg 22 of the header, via lines 44 and 48.Valves 50, 52 are opened/closed selectively to direct the discharge flowto the appropriate segment of the header depending on operation of theheat pump. In addition, a crossover line 54 between the intake anddischarge lines, on the pump side of the header connections, permitswater to be circulated through the heat pump during “shoulder” seasonswhen significant heating/cooling is not required; for recirculation, athree-way valve 46 is actuated to divert the discharge from the pump 40to the crossover line, preventing the discharge from flowing back to theheader, while the intake valve 42 can likewise be closed to prevent thepump from drawing from the header.

FIG. 5, in turn, shows the connections for a dehumidification heatingsource. The desiccant regeneration runaround 60 optimally intakes warmwater, which then picks up excess regeneration heat so that the water isdischarged at a higher temperature, i.e., as hot water. Therefore, ascan be seen in FIG. 5, the intake line 62 is connected to the warm waterleg 24 of the header, via an intake connection line 64, with water beingdrawn from the warm water leg 24 by a constant velocity pump 66. The hotwater from the unit exits through a discharge line 68, and throughconnector line 70 to the hot water leg 22 of the header. No connectionsare made to the cool water or chilled water legs 26, 28, since supplyfrom these legs is not needed to support operation of the system.Similar to the installation in FIG. 4, a crossover line 72 is mountedbetween the intake and discharge lines 62, 68 to permit recirculation ofthe water without drawing from/discharging to the header, flow throughthe crossover line being controlled by a three-way valve 74.

It will be noted that both the zone heat pump of FIG. 4 and thedehumidification heating source of FIG. 5 intake water from the warmwater leg 24 of the header. FIG. 6, in turn, shows the installation of asystem that discharges to the warm water leg rather than drawing fromit, specifically, a duct-mounted heating coil system 80. As can be seen,the duct-mounted heating coil system is supplied with water from the hotwater leg 22 of the header, by a variable volume pump 82 drawing throughthe intake line 84 and connector line 86. The duct heating coils heatthe interior of the building, using transfer air received from commonareas, after which the water exits the coils at a reduced temperatureand is discharged via lines 88 and 89 to the warm water leg of theheader. At or near the point of discharge on the warm water leg 24,another system that requires warm water draws water back out of theheader, such as the zone heat pump of FIG. 4 or dehumidification heatingsource of FIG. 5; since the warm water is already at or close to theoptimal intake temperature of the second system the efficiency of thelatter is maximized, and there is essentially no “waste heat” to thewarm water that is discharged from the first system.

FIG. 7, in turn, shows the installation of a system that utilizes excessheat from the building or other facility (e.g., excess heat generatedduring warm summer months) to heat water for a pool and also domesticpurposes. As can be seen, a heat recovery chiller 90 is connected via anintake line 82 to each of the hot water, warm water and cool water legs32, 34, 36 of the header, via respective connector lines 94, 96, 98 andcontrol valves 100, 102, 104. Water from any or all of these legs isdrawn through the intake line by a variable-volume pump 106 and suppliedto the heat recovery chiller 90, wherein heat is exchanged with water ina secondary loop 108. As can be seen, the secondary loop includes anintake line 110 from which water is drawn from the heat recovery chiller90 at an elevated temperature by pump 112, and is then supplied to heatexchangers 114, 116 for heating water for the pool and for domestic use,respectively. The water then flows back to the heat recovery chiller ata lower temperature, via the return line 118 of the secondary loop 108.The heat recovery chiller thus passes excess heat from the main header30 to the pool and domestic hot water supply. Water in the primary loopexits the heat recovery chiller 80 through discharge line 120 andreturns to either or all of the warm water, cool water or chilled waterlegs 34, 36, 38 of the header, via connector lines 122, 124, 126 andcontrol valves 128, 130, 132.

The intake control valves enable the heat recovery chiller to draw onany or all of the relatively “warm” legs on the header, depending on howmuch and from which zones the heat is to be extracted, while the returncontrol valves similarly enable the return flow to be directed to thezone or zones matching the output temperature; during summer when thereis a need for chilled water, which is drawn from the header by thevarious cooling system of the building/facility, the pool and domestichot water heat recovery chiller is preferably used to make chilled waterthat is discharged to leg 28 of the header, with the valves preferablybeing set up to draw from one of the two cooler of the “warm” legs 44,46 such that (given the temperature differential across the heatrecovery chiller 90) the return water will be at a suitably lowtemperature for discharge to the chilled water leg of the header. Duringperiods when the building or other facility is not producing excessheat, such as during winter for example, the pool and domestic heatrecovery chiller system will normally not be used, since there willgenerally not be excess heat to be removed from the thermal gradientheader 30.

FIGS. 8-14 show the connections of various additional systems to thethermal gradient header, each of which will be described below. In eachcase, the system intake picks up water from one or more points on theheader where the temperature is optimally matched to the requirements ofthe system and discharges water to points that most closely match theoptimal output temperature of the system, from which another system thenpicks up the water at a now optimal intake temperature for the latter'soperation; this preferably continues for all the relevant systems withinthe building or other facility, thus compounding the efficiency benefitsdescribed above. Furthermore, FIGS. 8-14 (as well as FIGS. 4-7)illustrate diagrammatically the ease with which system-to-headerconnections can be designed and installed throughout the building orother facility, given the preferred “back-and-forth” routing thatdefines the different temperature legs of the header.

FIG. 8 shows the installation of a water-to-air exhaust heat pump 140having an intake line 142 that is connected to both the warm water andcool water legs 24, 26 of the header, by connector lines 144, 146 andcontrol valves 148, 150. The discharge line 152, in turn, is connectedto the hot water and chilled water legs 22, 28, via connector lines 154,156 and control valves 158, 160. Water is drawn from the intake line 142by a constant velocity pump 162, from which it is circulated through theexhaust heat pump back to the discharge line 152. During summertime andother periods of warm ambient temperatures, the intake water is drawnfrom the cool water leg 26 of the header and discharged at a coolertemperature back to the chilled water leg 28; during this mode ofoperation, control valves 150 and 160 are open, while valves 148 and 158are closed. Then, during winter and other periods of cold weather, theintake water is drawn from the warm water leg 24 of the header anddischarged at a higher temperature back to the hot water leg 22, withthe arrangement of the control valves being reversed. A crossover line164 is installed between the intake and discharge lines 142, 152 forrecirculation of water through the exhaust heat pump when desired (e.g.,during “shoulder” seasonal periods), with flow through the crossoverrecirculation line being controlled by a three-way valve 166.

FIG. 9 shows the connections of a water cooled heat pump and DX coil170. As can be seen, water is supplied to the heat pump system by aconstant velocity pump 172, which draws from an intake line 174 that isconnected to the warm water and cool water legs 24, 26 of the header byconnector lines 176, 178 and control valves 180, 182. The water passesthrough the heat pump system, which includes a condenser section 184 forheating and an evaporator section 186 for cooling, and then returns tothe header via a discharge line 188 that is connected to the hot waterand chilled water legs 22, 28 by connector lines 190, 192 and controlvalves 194, 196. During summer or other periods of high ambienttemperature, the water cooled heat pump 170 draws from the warm waterleg of the header for cooling purposes, using evaporator section 186,and then returns the water at an elevated temperature to the hot waterleg 22; for dehumidification operation, the system similarly draws fromthe warm water leg of the header and discharges to the hot water leg.Then, during winter or other periods of cool ambient temperatures, thesystem draws from the cool water leg 26, for utilization by thecondenser section 184 for heating purposes, and returns the water at areduced temperature to the chilled water leg 28. The control valves 180,182, 194 and 196 are respectively opened/closed for the different modesof operation. Again, a crossover line 198 and three-way valve 199 areprovided for recirculation of water without drawing from/discharging tothe thermal gradient header, as desired.

FIG. 10 shows the connections of an outdoor air handling unit thatprovides makeup air to the living areas of the building or otherfacility. As can be seen, a constant velocity pump 202 supplies the airhandling unit with water drawn through intake line 204, which isconnected to the hot water leg 22 of the thermal gradient header byconnector line 206 and control valve 208, and to the chilled water leg28 by connector line 210 and control valve 212. The discharge line 214,in turn, is connected to the cool water leg 26 of the header byconnector line 216 and control valve 218, and to the chilled water leg28 by connector line 220 and control valve 222. During summer or othertimes of high ambient temperatures, chilled water is drawn from leg 28of the thermal radiant header, via line 210 and valve 212, and afterbeing utilized to cool the incoming warm air is discharged to the coolwater leg 26 of the header through valve 218 and connector line 216.During winter and other cold periods, in turn, hot water is drawn fromleg 22 of the header via connector line 206 and valve 208, and afterbeing utilized to warm the cold incoming air is discharged back toeither the cool water leg 265 or chilled water leg 28 of the header, viathe respective valves and connector lines. A crossover line 224 betweenthe intake and discharge lines 204 and a three-way valve 226 allow theair handling unit to re-circulate water without drawing from/dischargingto the header, during shoulder seasons and other times when heatingcooling of the outdoor air is not desired.

FIG. 11 shows the connections of an ice plant heat exchanger, such asmay be used with an ice plant for an ice rink, for example. Water issupplied to the ice plant heat exchanger 230 by a variable speed pump232 drawing through an intake line 234 that is connected to the warmwater/cool water and chilled water legs 24, 26, 28 of the thermalgradient header, by connector lines 236, 238, 240 and control valves242, 244, 246. Water exits the ice plant heat exchanger through adischarge line 248 that is connected to the hot water and warm waterlegs 22, 24 of the header by connector lines 250, 252 and control valves254, 256. The heat exchanger essentially picks up what would otherwisehave been waste heat from the ice plant, generated from therefrigeration process necessary to produce the ice, and transfers itinto the thermal gradient header for use by the other systems. Forexample, during summer or other times of high ambient temperatures, thevalves may be lined up so that the ice plant heat exchanger will drawfrom the warm water leg of the header, and then discharge the water at ahigher temperature back to the hot water leg 22. Similarly, duringwinter the system can draw from the chilled water or cool water legs 28or 26 to make warm water or hot water that is supplied back to legs 24or 22, and likewise during shoulder seasons the system may draw from thecool water leg 26 to make warm water or hot water supplied to legs 24 or22. The control valves 224, 244, 246, 254, 256 can be lined up toprovide any of the foregoing flow paths.

FIG. 12 shows the connections of an air handling unit that is associatedwith an ice rink that may be installed in conjunction with the ice plantof FIG. 11. As can be seen, water is supplied to the air handling unitby a constant velocity pump 262, drawing on an intake line 264 that isconnected to the hot water and chilled water legs 22, 28 of the thermalgradient header, by connector lines 266, 268 and control valves 270,272. Water exits the air handling unit through discharge line 274, whichis connected to the warm water and cool water legs 24, 26 of the headerby connector lines 276, 278 and control valves 280, 282. A crossoverline 284 interconnects the intake and discharge lines 264, 274, withflow therethrough being controlled by valve 286. During winter and otherperiods of cold weather, water is drawn from the hot water leg 22 andutilized to heat the cold air that is passing through the air handlingunit, with the outflow water being directed to either the warm water leg24 or cool water leg 26 depending on its temperature. However, duringsummer and other warm period, the air handling unit is generally usedfor ventilation only, with water circulating through the crossover line284 rather than being drawn from/discharged to the thermal gradientheader. The air handling unit can also be used for dehumidificationpurposes, with cold water being utilized to dehumidify the air passingthrough the unit; during dehumidification, chilled water is drawn fromleg 28 of the thermal gradient header and is returned at a highertemperature to the cool water leg 26.

For many installations, it will be preferable to design and install thevarious heating/cooling systems to operate at or near the low end oftheir designed circulation rate ranges (i.e., near the low end of theirpermitted circulation rates): This achieves the dual advantages ofmaximizing the thermal differential (γT) across each system, therebytypically increasing efficiency while providing an output temperaturecloser to that optimal for other systems (e.g., putting the output froman air conditioning system closer to the optimal intake temperature of awater heating systems), while reducing losses in terms of fluidtransportation/pumping energy. Lower pumping rates also tend to increaseefficiency by reducing the amount of flow that takes place within thethermal gradient header itself.

FIG. 13 shows the connections of a boiler loop hot water heat exchanger290. The purpose of this system is to be able to feed additional heatinto the header at times when the heat demand imposed on the header isbeyond that which the building's systems can provide en toto withouthelp from the boiler; such instances are anticipated to be comparativelyrare, due to the enhanced efficiencies described above, but may occur,for example, during periods of particularly cold weather. As can beseen, the intake line 292 is connected to the chilled water leg 28 ofthe header, by connector line 294 and control valve 296, with waterbeing drawn therefrom and supplied to the boiler loop heat exchanger 290by a variable volume pump 298. The heat exchange also receives hot waterfrom the boiler, such that the water circulating from the header exitsat a significantly higher temperature via discharge line 300, which isconnected to the hot water leg 22 of the header by connector line 302and control valve 304. At times when the thermal gradient header doesnot require additional heat beyond that which is provided by the othersystems besides the boiler, the valves 296, 304 and pump 298 are simplysecured, along with flow from the boiler to the heat exchanger andpossibly the boiler itself; this ability to minimize use of the boilerreflects the efficiency achieved by the present invention, and providessignificant cost savings over conventional buildings/facilities thatrequire frequent or even continuous operation of the boiler. It will beunderstood that other heat sources may be used to provide the make-upheat, in place of or in addition to a boiler, such as a geothermal heatsource, for example.

FIG. 14, in turn, shows the connections of a fluid cooler system 310which serves a converse purpose relative to the boiler heat exchanger ofFIG. 13, i.e., to remove excess heat from the thermal gradient headerbeyond that which can be extracted and used by the other systems; again,this is anticipated to be a comparatively rare situation due to theefficiencies achieved by the thermal gradient header, but may occur, forexample, during periods of hot weather when the building/facilityproduces too much heat. Accordingly, the intake line 312 is connected tothe hot water leg 22 of the thermal gradient header, via connector line314 and control valve 316, with water being drawn therefrom and suppliedto the cooler by a variable volume pump 318. After passing through thecooler, the water returns at a lower temperature via discharge line 320,which is connected to the warm water leg 24 of the header by connectorline 322 and control valve 324. The excess heat removed by the fluidcooler may simply be passed to the outside air or otherwise rejected, insome instances, however, it may be supplied (e.g., using piped water) toa geothermal reservoir or the like, from which the heat can subsequentlybe recovered and supplied back to the thermal gradient header at timeswhen additional heat is needed, similar to the manner in whichadditional heat is provided by the boiler loop heat exchanger of FIG.13. Storage in a geothermal reservoir, such as a ground source thermalfield or “battery” provides very significant advantages over traditionalground-source heating systems, since typically the latter only draw heatfrom the field until the ground is completely chilled (“frozen”) and thefield is useless, whereas by adding excess heat from the thermal headerwhen available the life of the ground source field can be extendedindefinitely. Moreover, given the thermal input from the header of thepresent invention, the ground source field can be greatly reduced insize while still providing the same capacity for heating, resulting insignificantly reduced installation costs.

Control technology for operating the pumps and valves associated withthe various systems that are connected to the legs of the thermalgradient header is well known to those skilled in the relevant art.Furthermore, it will be understood that the various systems andconnections that are shown in FIGS. 4-14 are provided by way ofillustration rather than limitation and that the connections may varydepending on actual system requirements, and furthermore that variousother systems may be connected to the thermal gradient header dependingon the type of building or other facility. Still further, it will beunderstood that the size, capacity routing and so on of the thermalheader, and the various connections thereto, will vary with the type ofbuilding or facility, the types and numbers of systems, and other designfactors.

The block diagrams of 15 and 16 offer a schematic comparison of thethermal losses of a typical prior art system and the thermal gradientheader system of the present invention.

As can be seen in FIG. 15, which illustrates a typical prior artinstallation, cooling and heating systems operate largely impendent ofone another: For example, a heat source may provide heating to a heatload, such as a living space, while a cooling source provides cooling(i.e., draws heat from) a cooling load such as an ice rink or forrefrigeration. Conventionally, a degree of heat reclaimed from thecooling source may be supplied to the heat load so as to indirectlyreduce the load on the heat source. However, when heat reclamation isnot required for the heat load, excess heat from the cooling source issimply rejected to the environment, as indicated by the arrow at thelower right. Similarly, excess heat from the cooling load is typicallydischarged by means of free cooling, e.g., simple ventilation to theoutside air. In this example, therefore, both free cooling and rejectedheat represent very significant losses of thermal energy.

By comparison, as shown in FIG. 16 and also FIG. 17, the thermalgradient header is shared by all of the heating and cooling loads in afacility 10, so that a thermal output from one system is taken in andused by another. For example, as is shown and as described above, theheated by cooling loads (e.g., cooling systems 330, 332) is dischargedat increased temperatures of outlets disposed towards the warm end 334 othe header 22, where it is take n up by systems that utilize the waterat higher temperatures, while the water chilled by heating loads (e.g.,heating systems 336, 338) is discharged towards the cool end 340 of theheader, where it can be taken up by systems employing the water at lowertemperature. As a result, very little thermal energy (in someinstallations none) needs to be added by a heat source (such as aboiler) connected at one end of the header and/or rejected by a coolingsource connected at the other. Moreover, what little heat may need to berejected can be supplied to a geothermal field or other reservoir forreuse later. Thermal losses are therefore almost nil by comparison withthe prior art type of installation shown in FIG. 15.

It is to be recognized that various alterations, modifications, and/oradditions may be introduced into the constructions and arrangements ofparts described above without departing from the spirit or ambit of thepresent invention.

What is claimed is:
 1. Apparatus for increasing efficiency of heatingand cooling systems for buildings and other facilities, said apparatuscomprising: an elongate thermal gradient header having at least one zonecontaining fluid at a relatively higher temperature and at least onezone containing fluid at a relatively lower temperature; and a pluralityof heating/cooling systems that draw said fluid from said thermalgradient header and discharge said fluid back thereto, each of theheating/cooling systems having an intake connected to a first one of thezones of the header that contains said fluid at a temperature closer toan optimal intake temperature of the heating/cooling system, and adischarge connected to a second of said zones that contains said fluidat a temperature that is closer to an optimal discharge temperature ofsaid system.
 2. The apparatus of claim 1, wherein said plurality ofheating/cooling systems comprises: multiple heat/cooling systems thatoperate in combination in a facility, that are connected to said thermalgradient header such that at least one of said systems draws from a zoneof said header fluid that has been discharged to said zone by at leastone other of said heating/cooling systems.
 3. The apparatus of claim 2,wherein said thermal gradient header comprises: an elongate pipecontaining said fluid.
 4. The apparatus of claim 3, wherein said fluidcontained in said elongate pipe is water.
 5. The apparatus of claim 3,wherein said zones of said header comprise: temperature zones formed bylegs of said elongate pipe that are routed through said facility.
 6. Theapparatus of claim 5, wherein said heating/cooling systems connected tosaid thermal gradient header comprise: heating/cooling systems connectedto said legs and said pipe that are routed through said facility.
 7. Theapparatus of claim 6, wherein said heating/cooling systems are selectedfrom the group consisting of: heat pumps; air handling units; airconditioning units; refrigeration units; water heaters; ice plants; andcombinations thereof.
 8. The apparatus of claim 3, further comprising:means connected to said thermal gradient header for providing makeupheat as necessary.
 9. The apparatus of claim 8, wherein said means forproviding makeup heat comprises: a boiler heat exchanger.
 10. Theapparatus of claim 3, further comprising: means connected to saidthermal gradient header for rejecting excess heat as necessary.
 11. Theapparatus of claim 10, wherein said means for rejecting excess heatcomprises: a fluid cooler.
 12. The apparatus of claim 10, wherein saidmeans for rejecting excess heat comprises: a thermal reservoir fromwhich heat may be recovered during a subsequent period of operation. 13.The apparatus of claim 12, wherein said thermal reservoir comprises: aground source thermal field.
 14. The apparatus of claim 3, wherein saidthermal gradient header comprises: multiple legs, each leg containingfluid at progressively cooler temperatures from hot to cold.
 15. Theapparatus of claim 14, wherein said multiple legs of said thermalgradient header comprise, progressively: a hot water leg; a warm waterleg; a cool weather leg; and a chilled water leg.
 16. The apparatus ofclaim 15, wherein said legs of said thermal gradient header comprises:legs defined by runs of said pipe routed with said facility.
 17. Theapparatus of claim 16, wherein said rungs of said pipe are routed backand forth between a mechanical room and distribution areas of saidfacility.
 18. The apparatus of claim 15, further comprising: a pluralityof pumps associated with said heating/cooling systems, that eachcirculate said fluid from a first leg of said header, through saidassociated system, and back to a second leg of said header.
 19. Theapparatus of claim 18, further comprising: a plurality of intake anddischarge lines connecting said heating/cooling systems to said header,through which said fluid is circulated by said pumps.
 20. The apparatusof claim 19, further comprising: one or more crossover lines thatinterconnect said intake and discharge lines, so that said fluid can beselectively circulated through said heating/cooling systems withoutbeing drawn from/discharged to said thermal gradient header.
 21. Theapparatus of claim 19, further comprising: one or more control valvesthat are selectively operable to allow said pumps associated with saidheating/cooling systems to draw from/discharge to different legs of saidthermal gradient header depending on operating conditions of saidheating/cooling systems.
 22. A method for increasing efficiency ofheating and cooling systems for buildings and other facilities, saidmethod comprising the steps of: providing an elongate thermal gradientheader having at least one zone containing a fluid at a relativelyhigher temperature and at least one zone containing said fluid at arelatively lower temperature; and supplying said fluid from the thermalgradient header to a plurality of heating/cooling systems, the step ofsupplying said fluid from the thermal gradient header to said pluralityof heating/cooling systems comprising drawing said fluid from saidthermal gradient header for each heating/cooling system from a first oneof the zones that contains said fluid at a temperature closer to anoptimal intake temperature of that system, and then discharging saidfluid from the system to a second of the zones of the header thatcontains the fluid at a temperature that is closer to an optimaldischarge temperature of that system.
 23. The method of claim 22,wherein the step of discharging said fluid back to said second zone ofsaid thermal gradient header comprises: discharging said fluid back at alower temperature/higher temperature than that at which said fluid isdrawn from said first zone of said header.
 24. The method of claim 23,wherein the step of supplying fluid from said thermal gradient header toa plurality of heating/cooling systems comprises: supplying said fluidto multiple/heating systems that operate in combination in a facility,said heating/cooling systems being connected to said thermal gradientheader so that certain of said systems draw from zones of said headerfluid that has been discharged to said zones at near optimal intaketemperatures by others of said heating/cooling systems.
 25. The methodof claim 24, wherein the step of providing a thermal gradient headercomprises: providing an elongate pipe that contains said fluid.
 26. Themethod of claim 25, wherein said fluid is water.
 27. The method of claim25, wherein the step of providing said thermal gradient header furthercomprises: routing said elongate pipe in said facility so as to formmultiple legs of said header that define said temperature zones thereof,said temperature zones containing said fluid at progressively coolertemperatures from hot to cold.
 28. The method of claim 27, wherein thestep of providing fluid from said thermal gradient header to saidplurality of heating/cooling systems comprises: drawing fluid fromsupply legs of said header using pumps that are associated with saidheating/cooling systems; circulating said fluid through saidheating/cooling systems; and discharging said fluid from saidheating/cooling systems back to receiving legs of said header.
 29. Themethod of claim 28, wherein the step of supplying said fluid to aplurality of heating/cooling systems further comprises the step of:selectively operating one or more control valves so as to allow saidheating/cooling systems to draw from/discharge to different legs of saidthermal gradient header, depending on operating conditions of saidheating/cooling systems.